If your Windows chops extend in any capacity beyond novice, you’ve no doubt encountered the ever-cryptic Windows Registry, DLL files, User Account Control, and other tools with seemingly dark and mysterious powers. Here, we’ll explain some of Windows’ most confusing features, so you know exactly what’s happening when you go to edit them.

Blast from the past is a weekly feature at Lifehacker in which we revive old, but still relevant, posts for your reading and hacking pleasure. In honor of the Windows 10 launch, we’re revisiting one of our favorite Windows explainers.

Some of these things you may already know about, but others may be unknown to even the tech savvier among you (I know I learned a few things writing this piece). We’ll be covering 5 different Windows tools here: the registry, DLL files, User Account Control, drivers, and the Group Policy Editor. Scroll down to see more about what these things are, how they work, and what you can do with them.

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The Registry

The registry is one of Windows’ most confusing tools, but it can also be very powerful if you know what you’re doing. The registry is, essentially, a hierarchical database that stores settings and preferences for nearly everything on your system, from drivers and services to your user passwords and user interface. In the old days of Windows, application preferences were stored in text files with the INI extension, and while some still are, they’ve been ditched for the faster, unified registry.

You can edit the registry yourself, if you wish (though you usually need to know what registry “key” you’re tweaking before you go in, since they aren’t very descriptive). Just open the Start menu and type regedit into the search box. From there, you can navigate the tree in the left sidebar, and double-click on the desired key in the right pane to edit it. You might also find, in your daring travels, that some people try to save you trouble by creating .reg files that make the desired registry tweaks with a double click. I’d recommend opening these up with Notepad to make sure they’re actually editing the right registry keys (after all, it’d be pretty easy to muck up one’s computer this way if one was so inclined), but as long as everything looks kosher, they’re a quick and easy way to tweak your system.

The Windows registry is a mysterious place, but if you're comfortable editing it, you have the …
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Problems That Can Arise with the Registry

While the registry offers some advantages over INI files (mainly speed), it isn’t without problems. Putting all your eggs in one basket always poses a risk. If something were to damage the registry, it could potentially cause problems with your entire Windows installation, not just that one program—which means you’d need to repair the registry or reinstall Windows altogether. This is why registry hacks, though useful, always come with the disclaimer to back up your registry first, as things can go very, very wrong very, very quickly. The registry can also build up a lot of junk if you don’t uninstall applications properly, or if the app uninstallers are poorly written.

There's nothing more mysterious on a Windows PC than the Registry, and today we'll…
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Dynamic-Link Libraries (DLLs)

Dynamic-Link Libraries, usually found on your system as .DLL files, are libraries of code that any program can use. They serve two purposes:

Since multiple programs can use them at the same time, it encourages people to reuse code, meaning your RAM has to load fewer things and your computer runs a little faster. Dialog boxes are a great example: Since the Comdlg32 DLL can be used by any program, you don’t need a bunch of programs loading their own dialog box-related code; they just use the code built into Windows.

DLLs allow programs to be modular. That is, it allows a program to call on only certain pieces of code rather than loading everything at once, which can slow the program down. You’ll find this a lot with plugin-based programs, like Rainmeter or foobar2000. They’ll only load the features you actually use, which they can do because DLLs exist separately from one another. You can also add more features to them by adding DLL files of your own.

DLLs can also make updating a program simpler, since you won’t always have to reinstall the program from scratch—it can just update the necessary DLL files. But, all in all, it makes your system run a bit faster and it allows for customizable, plugin-based programs, which we’re pretty big fans of.

Examples of DLL-Related Life Hacks

Problems That Can Arise with DLL Files

The most common problem people see with DLL files is that they go missing. This problem isn’t quite as prevalent as it used to be, at least in my experience, but it’s good to know what to do if it does happen. If you get a “____.dll missing” error from a program, you’ll probably be tempted to go find the DLL file and download it, but that isn’t always the best idea. Instead of heading to a site like DLL-Files.com, you’re better off reinstalling the program from scratch, or at least running the “repair” option in its installation (if it has one). Usually, it’ll replace whatever it needs, unless there’s something wrong with the program itself (which a quick Google can help you figure out).

If you find this happens more than once in a blue moon, there’s probably something else going on. Make sure you have good antivirus software running and that you perform regular scans—if DLL files are missing left and right, it’s likely that you have some malware on your system, and replacing the DLL files is just going to be a Band-Aid on a bullet wound.http://lifehacker.com/5865356/the-be...

Windows has more antivirus programs than we can count, and none of them are quite perfect. Right…
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User Account Control (UAC)

User Account Control is a security feature in Windows Vista and above that only sort of does what it sounds like. Essentially, User Account Control (UAC) is a way for certain programs to ask your permission before performing system-level changes—like if you’re installing a new program or editing system files. That way, malicious programs can’t just run without your consent—you’re forced to more closely pay attention to which programs have permission to tweak the system.

By default, UAC is set to always notify you when programs try to make changes, but not when you make changes to Windows settings. By heading to User Account Control Settings (which you can search for in the Start Menu’s search box), you can make UAC more or less strict, the least strict option being that it never notifies you of any changes. I like to slide it down one notch—to the second from the bottom—since my screen usually takes a long time to dim when popping up UAC prompts, and lowering the UAC level fixes this. Turning it off completely isn’t recommended unless you really know what you’re doing, since it can let any program run without your express permission.

Examples of UAC-Related Life Hacks

While you can’t do much with the UAC, it is something that a lot of tricks require you turn off, so it’s important to know what you’re doing when you bring that slider down. Here are some examples of hacks that require UAC to be turned off:

Problems That Can Arise with UAC Tweaks

Changing the UAC level isn’t going to ruin your computer like a bad registry or missing DLL file might, but installing something you don’t trust will—and UAC makes that just a little bit easier, since it won’t require those programs to prompt you. The best thing we can say is that UAC is not a sufficient security tool—always remember to keep a good antivirus program around. Even at its most strict, UAC won’t be able to tell viruses from regular programs; it just asks you whether you want to run certain things or not. Responsibility is the best protection against malware.

Drivers

Many of you may already know what drivers are, though they are still considered a “dark corner” by many—and it’s important to know not only what they are, but how to manage them properly. A driver is a piece of software that allows your hardware to communicate with Windows. So, whether that means helping your computer communicate with your network card to access the internet or communicate with your webcam so you can broadcast video over Skype, nearly all the hardware on your computer has a Windows driver that allows it to work. Many drivers are built into Windows, while some you need to get from that hardware manufacturer’s web site. Sometimes Windows has a barebones version of the driver built-in, and even though your hardware will work out of the box, downloading the official manufacturer driver will give you more features.

Examples of Driver-Related Life Hacks

While I don’t really recommend using all-in-one driver update utilities, there are still a few useful tricks we’ve learned over the years when it comes to dealing with drivers:

How to Correctly Manage Your Drivers

When you first install a new piece of hardware, head to the manufacturer’s web site and download the latest drivers (don’t install the ones on the CD that came with it). This ensures that you have the latest ones, and that you have the official ones from that company, not the half-assed Microsoft drivers that may not update as often or come with extra features. That said, for certain things—like printers—the Microsoft drivers can be better since they don’t install tons of other unnecessary software. You need to judge it on a driver-by-driver basis depending on your needs.

When it comes to updating drivers, don’t do it willy-nilly. If your driver is working fine, then there’s no reason to upgrade unless the new version has some awesome feature or speed enhancement you want. That means video card drivers are often the exception to this rule—each upgrade usually comes with speed enhancements and profiles for new games, so if you’re a gamer, you’ll want to take advantage of new video card drivers when you can. Of course, if the new ones start to cause problems, you can always roll back, so make a note of what version you’re currently using every time before you upgrade.http://lifehacker.com/5912682/do-i-r...

Dear Lifehacker, I recently updated my video drivers and discovered that a lot of my other drivers…
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To check your driver version for any particular driver, just head to the Device Manager (by going to Start and searching for Device Manager), right-clicking on the hardware in question, and going to the driver tab. That will list your driver version, and you can compare that with the current version on the manufacturer’s web site to see if there’s a newer version available. You can then download the newer version from the manufacturer and install it. I usually avoid updating drivers from the Device Manager, since I never really know what I’m getting—I like to download it straight from the manufacturer itself.

The Group Policy Editor

The Group Policy Editor is a tool you may have heard less about, but it does come up from time to time. It’s only available on Windows Professional and higher, so not all users will have it, but it can do some pretty cool things. On the surface, its purpose is to control what users can and can’t do, usually in enterprise situations. If you have a computer and you want to block its users from editing the registry, changing security settings, or installing software, the Group Policy Editor is how you would change that. We’ve featured a few of these features before—namely creating an application whitelist and blocking certain hard drives—but it can do some other cool things, too.

Editing group policy isn’t all that different from editing the registry. Head to the Start menu, type in Group Policy, and click on the editor that pops up. You’ll have a sidebar on the left with a hierarchical listing of settings you can tweak, both for the computer and the current user, and when you find something you want to change, you can right click on it in the right-hand pane to create a new policy. Like the registry, group policy is also pretty darn cryptic, so you’ll probably need to know what you want to do before heading into the editor, so you know which settings to edit and what values to give their policies.

Examples of Group Policy-Related Life Hacks

Got any of your own tips related to the above features? Share them in the comments. And if you have any other Windows features you’d like explained, let us know—there are a lot more dark Windows corners to be explored!